1. Field of the Invention
The present invention is related to alien near end crosstalk (NEXT) compensation and, more particularly, to alien NEXT compensation for standalone unshielded twisted pair (UTP) connectors that are adjacently placed.
2. Discussion of the Related Art
Noise or signal interference between conductors of connectors that are adjacently placed is known as alien NEXT. FIG. 1 shows two UTP modular outlet connectors 1 and 2 that are placed side by side, e.g., in a wall outlet. The connectors 1 and 2 are identical to each other and the configuration of such connectors is known.
As shown in FIG. 1, each of the connectors 1 and 2 includes a printed circuit board (PCB) 50, a plurality of insulation displacement contacts (IDCs) 52, and a plurality of spring wire contacts 54 that are disposed above the PCB 50 and appropriately connected to the IDCs 52 by means of conductive traces on the PCB 50. The IDCs 52 on each of the connectors 1 and 2 are grouped into four pairs P1–P4, where each pair is made up of a ring conductor designated by (r) and a tip conductor designated by (t). As is known, the term “ring” refers to the negatively polarized conductor of the pair, while the term “tip” refers to the positively polarized conductor of the pair.
Each of the IDCs 52 includes a top part 52a having a slit 52c therein and a bottom part 52b to be inserted into a corresponding plated through hole 56 disposed within the PCB 50. For the sake of brevity, only one hole 56 is shown in FIG. 1, but the PCB 50 has multiple plated through holes 56 for receiving therein the corresponding bottom parts 52b of the IDCs 52. Generally, the spring wire contacts 54 mate with externally provided connectors, and electrical wires are inserted into the slits 52c of the IDCs 52 as known.
Although effective, a limitation with the configuration of the connectors 1 and 2 is that when they are placed side by side, capacitive coupling and inductive coupling between the IDCs 52 of the two connectors cause alien NEXT. The alien NEXT level is highest between the pairs of the IDCs 52 facing each other in the two connectors. In this example, the alien NEXT level will be highest between the second pair P2 (r2 and t2) of the connector 1 and the first pair P1 (r1 and t1) of the connector 2 and also between the third pair P3 (r3 and t3) of the connector 1 and the fourth pair P4 (r4 and t4) of the connector 2. Such alien NEXT impairs the signals propagating through the connectors. This problem is not limited to the connectors 1 and 2, but is present in other types of connectors when they are placed adjacently without any shielding mechanism.
Therefore, there is a need to suppress or compensate for the alien NEXT in adjacently placed connectors, such that it is reduced to minimal or acceptable levels (e.g., levels that would support 10 gigabit Ethernet) without the need to shield these connectors from each other.